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<HTML><!--Distributed by F --><HEAD><TITLE>[Chapter 3] 3.4 Automatic File Cleanup </TITLE><METANAME="DC.title"CONTENT="UNIX Power Tools"><METANAME="DC.creator"CONTENT="Jerry Peek, Tim O'Reilly & Mike Loukides"><METANAME="DC.publisher"CONTENT="O'Reilly & Associates, Inc."><METANAME="DC.date"CONTENT="1998-08-04T21:32:32Z"><METANAME="DC.type"CONTENT="Text.Monograph"><METANAME="DC.format"CONTENT="text/html"SCHEME="MIME"><METANAME="DC.source"CONTENT="1-56592-260-3"SCHEME="ISBN"><METANAME="DC.language"CONTENT="en-US"><METANAME="generator"CONTENT="Jade 1.1/O'Reilly DocBook 3.0 to HTML 4.0"><LINKREV="made"HREF="mailto:online-books@oreilly.com"TITLE="Online Books Comments"><LINKREL="up"HREF="ch03_01.htm"TITLE="3. Logging Out"><LINKREL="prev"HREF="ch03_03.htm"TITLE="3.3 Electronic Fortune Cookies "><LINKREL="next"HREF="ch03_05.htm"TITLE="3.5 Stop Accidental C Shell Logouts "></HEAD><BODYBGCOLOR="#FFFFFF"TEXT="#000000"><DIVCLASS="htmlnav"><H1><IMGSRC="gifs/smbanner.gif"ALT="UNIX Power Tools"USEMAP="#srchmap"BORDER="0"></H1><MAPNAME="srchmap"><AREASHAPE="RECT"COORDS="0,0,466,58"HREF="index.htm"ALT="UNIX Power Tools"><AREASHAPE="RECT"COORDS="467,0,514,18"HREF="jobjects/fsearch.htm"ALT="Search this book"></MAP><TABLEWIDTH="515"BORDER="0"CELLSPACING="0"CELLPADDING="0"><TR><TDALIGN="LEFT"VALIGN="TOP"WIDTH="172"><ACLASS="SECT1"HREF="ch03_03.htm"TITLE="3.3 Electronic Fortune Cookies "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 3.3 Electronic Fortune Cookies "BORDER="0"></A></TD><TDALIGN="CENTER"VALIGN="TOP"WIDTH="171"><B><FONTFACE="ARIEL,HELVETICA,HELV,SANSERIF"SIZE="-1">Chapter 3<BR>Logging Out</FONT></B></TD><TDALIGN="RIGHT"VALIGN="TOP"WIDTH="172"><ACLASS="SECT1"HREF="ch03_05.htm"TITLE="3.5 Stop Accidental C Shell Logouts "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 3.5 Stop Accidental C Shell Logouts "BORDER="0"></A></TD></TR></TABLE> <HRALIGN="LEFT"WIDTH="515"TITLE="footer"></DIV><DIVCLASS="SECT1"><H2CLASS="sect1"><ACLASS="title"NAME="UPT-ART-1110">3.4 Automatic File Cleanup </A></H2><PCLASS="para"><ACLASS="indexterm"NAME="AUTOID-4081"></A><ACLASS="indexterm"NAME="AUTOID-4083"></A><ACLASS="indexterm"NAME="AUTOID-4086"></A><ACLASS="indexterm"NAME="AUTOID-4088"></A><ACLASS="indexterm"NAME="AUTOID-4091"></A><ACLASS="indexterm"NAME="AUTOID-4094"></A>If you use a<SPANCLASS="link">system to make temporary files (<ACLASS="linkend"HREF="ch21_03.htm"TITLE="Unique Names for Temporary Files ">21.3</A>)</SPAN>,your <EMCLASS="emphasis">.logout</EM> file can clean up the temporary files.The exact cleanup command you'll use depends on how you create the files,of course.The overall setup looks something like this in <EMCLASS="emphasis">.logout</EM>:</P><PCLASS="para"><TABLECLASS="screen.co"BORDER="1"><TR><THVALIGN="TOP"><PRECLASS="calloutlist"><ACLASS="co"HREF="ch14_11.htm"TITLE="14.11 Finding (Anyone's) Home Directory, Quickly ">~</A> </PRE></TH><TDVALIGN="TOP"><PRECLASS="screen">(set nonomatch; cd ~/temp && rm -f *) &</PRE></TD></TR></TABLE></P><PCLASS="para">The parentheses run the commands in a<SPANCLASS="link">subshell (<ACLASS="linkend"HREF="ch13_07.htm"TITLE="The () Subshell Operators ">13.7</A>)</SPAN><ACLASS="indexterm"NAME="AUTOID-4105"></A>so the <EMCLASS="emphasis">cd</EM> commandwon't change the current shell's working directory.<ACLASS="indexterm"NAME="AUTOID-4108"></A><ACLASS="indexterm"NAME="AUTOID-4111"></A>The C shell needs a<SPANCLASS="link"><CODECLASS="literal">set</CODE> <CODECLASS="literal">nonomatch</CODE> (<ACLASS="linkend"HREF="ch15_04.htm"TITLE="What if a Wildcard Doesn't Match? ">15.4</A>)</SPAN>command so the shell will be quiet if therearen't any <CODECLASS="literal">temp</CODE> files to clean up;omit that command in Bourne-type shells.The<SPANCLASS="link"><CODECLASS="literal">&&</CODE> (<ACLASS="linkend"HREF="ch44_09.htm"TITLE="Testing Your Success ">44.9</A>)</SPAN>means that <CODECLASS="literal">rm</CODE> won't run unless the <CODECLASS="literal">cd</CODE> succeeds.Using <CODECLASS="literal">cd ~/temp</CODE> first, instead of just <CODECLASS="literal">rm ~/temp/*</CODE>,helps to keep <EMCLASS="emphasis">rm</EM>'s command-line arguments from<SPANCLASS="link">getting too long (<ACLASS="linkend"HREF="ch15_06.htm"TITLE="Maybe You Shouldn't Use Wildcards in Pathnames ">15.6</A>)</SPAN>if there are lots of temporary files to remove.</P><PCLASS="para">If you could be logged in more than once, be careful not to remove <CODECLASS="literal">temp</CODE>files that other login sessions might still be using.One way to do this is with the<ACLASS="indexterm"NAME="AUTOID-4127"></A><SPANCLASS="link"><EMCLASS="emphasis">find</EM> (<ACLASS="linkend"HREF="ch17_02.htm"TITLE="Delving Through a Deep Directory Tree ">17.2</A>)</SPAN>command - only remove files thathaven't been modified in the last day:</P><PCLASS="para"><TABLECLASS="screen.co"BORDER="1"><TR><THVALIGN="TOP"><PRECLASS="calloutlist"><ACLASS="co"HREF="ch09_21.htm"TITLE="9.21 Handle Too-Long Command Lines with xargs ">xargs</A> </PRE></TH><TDVALIGN="TOP"><PRECLASS="screen">find ~/temp -type f -mtime +1 | xargs rm -f &</PRE></TD></TR></TABLE></P><DIVCLASS="sect1info"><PCLASS="SECT1INFO">- <SPANCLASS="authorinitials">JP</SPAN></P></DIV></DIV><DIVCLASS="htmlnav"><P></P><HRALIGN="LEFT"WIDTH="515"TITLE="footer"><TABLEWIDTH="515"BORDER="0"CELLSPACING="0"CELLPADDING="0"><TR><TDALIGN="LEFT"VALIGN="TOP"WIDTH="172"><ACLASS="SECT1"HREF="ch03_03.htm"TITLE="3.3 Electronic Fortune Cookies "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 3.3 Electronic Fortune Cookies "BORDER="0"></A></TD><TDALIGN="CENTER"VALIGN="TOP"WIDTH="171"><ACLASS="book"HREF="index.htm"TITLE="UNIX Power Tools"><IMGSRC="gifs/txthome.gif"SRC="gifs/txthome.gif"ALT="UNIX Power Tools"BORDER="0"></A></TD><TDALIGN="RIGHT"VALIGN="TOP"WIDTH="172"><ACLASS="SECT1"HREF="ch03_05.htm"TITLE="3.5 Stop Accidental C Shell Logouts "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 3.5 Stop Accidental C Shell Logouts "BORDER="0"></A></TD></TR><TR><TDALIGN="LEFT"VALIGN="TOP"WIDTH="172">3.3 Electronic Fortune Cookies </TD><TDALIGN="CENTER"VALIGN="TOP"WIDTH="171"><ACLASS="index"HREF="index/idx_0.htm"TITLE="Book Index"><IMGSRC="gifs/index.gif"SRC="gifs/index.gif"ALT="Book Index"BORDER="0"></A></TD><TDALIGN="RIGHT"VALIGN="TOP"WIDTH="172">3.5 Stop Accidental C Shell Logouts </TD></TR></TABLE><HRALIGN="LEFT"WIDTH="515"TITLE="footer"><IMGSRC="gifs/smnavbar.gif"SRC="gifs/smnavbar.gif"USEMAP="#map"BORDER="0"ALT="The UNIX CD Bookshelf Navigation"><MAPNAME="map"><AREASHAPE="RECT"COORDS="0,0,73,21"HREF="../index.htm"ALT="The UNIX CD Bookshelf"><AREASHAPE="RECT"COORDS="74,0,163,21"HREF="index.htm"ALT="UNIX Power Tools"><AREASHAPE="RECT"COORDS="164,0,257,21"HREF="../unixnut/index.htm"ALT="UNIX in a Nutshell"><AREASHAPE="RECT"COORDS="258,0,321,21"HREF="../vi/index.htm"ALT="Learning the vi Editor"><AREASHAPE="RECT"COORDS="322,0,378,21"HREF="../sedawk/index.htm"ALT="sed & awk"><AREASHAPE="RECT"COORDS="379,0,438,21"HREF="../ksh/index.htm"ALT="Learning the Korn Shell"><AREASHAPE="RECT"COORDS="439,0,514,21"HREF="../lrnunix/index.htm"ALT="Learning the UNIX Operating System"></MAP></DIV></BODY></HTML>⌨️ 快捷键说明
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